The present invention relates to a burner in an air stream used for the direct heating of air or of combustion gas from turbines or engines and more particularly to the in-stream burner module the side-by-side juxtaposition of which on manifolds constitutes the in-stream burner. This type of burner uses as oxidant the turbine exhaust gases (TEG) or engine exhaust gases that have an oxygen concentration (in wet smoke) lower than the ambient air, a temperature higher than the ambient temperature and, generally, a speed on exiting the burner that is relatively low, and as fuel natural gas, shale gas, oil gas or gases coming from industrial processes.